Instabilities, turbulence and heat transfer in confined rotating flows

This habilitation thesis sums up 8 years of experimental and numerical investigations in the fields of fluid mechanicsand heat transfer. It is directly in line with my PhD thesis on the stability and turbulence of rotor-stator interdisk flowswith throughflow. It gave place to 12 publications in international journals of rank A. The following 9 flow arrangementsdivided into two main parts have been thus considered and studied in details in this monograph:1. Part 1: Rotating disk flows: Similarity solutions of the flow of a non-Newtonian fluid over an infinite stationary rough disk; Stability of the flow over a finite rotating disk with a free surface; Stability and transition to turbulence of enclosed rotor-stator disk flows; Fully turbulent regime of enclosed rotor-stator disk flows under isothermal and non-isothermal conditions; Turbulent Von K´arm´an swirling flows between two rotating disks equipped or not with straight blades; Impinging jet flow over a rotating disk with heat transfer.2. Part 2: Flows induced by the differential rotation of concentric cylinders: Stability of Taylor-Couette flows with radial thermal gradients; Transitional and turbulent flows in a Taylor-Couette apparatus with atypical boundary conditions; Turbulent Taylor-Couette-Poiseuille flows with or without heat transfer.These works are either fundamental or find some applications in geophysics (Earth’s mantle convection, zonal winds,ocean currents . . . ) and in the turbomachinery industry. Almost all rotating machineries are indeed composed of rotorstatorcavities, where high rotation rates are reached in very small clearances, which may induce large overheatings.The first Part of this thesis has been mainly motivated by some industrial contracts with the SNECMA Moteurs group,which develops the liquid hydrogen turbopump of the Vulcain engine (Ariane V) with the goal to better predict theaxial thrusts applied on the rotor. The final goal of the second Part was to improve the cooling of an electrical motordeveloped by Liebherr Aerospace Toulouse.High-order numerical tools have been then developed for these specific applications. Two codes based on thesame projection and temporal schemes have been used with different spatial schemes: code 1 is based on Chebyshevpolynomials for the spatial discretization in the non homogeneous directions, whereas code 2 is based on 4th ordercompact finite-difference schemes. Both codes have been extended to Large Eddy Simulation using either the SVVtechnique for code 1 or more classical subgrid scale modelings for code 2. They are both available in their multidomainapproach using the matrix influence technique, which enables to take into account either complex geometries, highaspect ratio cavities or atypical boundary conditions. An innovative Reynolds Stress Model sensitized to rotation effectshas also been widely used to cover high turbulent flow regimes.These in-house numerical tools have been compared also to other numerical approaches available within commercialor open source CFD codes through different numerical benchmarks. They have been systematically validated againstexperimental data obtained either by flow visualizations or by velocity measurements performed by Laser DopplerVelocimetry or Particle Image Velocimetry.Rotating flows in confined systems are still an alive topic of research. The route to turbulence in some specific casesis not yet fully understood and there is clearly a lack of numerical and experimental studies of non-Newtonian rotatingfluid flows for applications in process or food engineering